Blood vessel transecting and anastomosis

ABSTRACT

Method and device for cutting a blood vessel using a cutting tool from within the blood vessel. A first cut portion of the blood vessel is fused to a second blood vessel to provide a flow channel therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e), to U.S.Provisional Application No. 60/638,808, filed Dec. 23, 2004, which isincorporated by reference into this application as if fully set forthherein.

BACKGROUND OF THE INVENTION

Patients suffering from reduced renal function or renal failure oftenhave to undergo hemodialysis treatments. During dialysis, blood iswithdrawn from the patient and is circulated through a hemodialysismachine. The machine removes toxic waste products and returns thepurified blood to the patient. Typically, dialysis treatments areperformed three times a week for the duration of a patient's life unlessa kidney transplant procedure occurs. To successfully undergohemodialysis treatment, blood is typically circulated through thehemodialysis machine at approximately 150 to 600 ml/minute flow rate forabout 3-4 hours. Blood flow from the venous system is inadequate to meetthe required flow rate and repeated punctures of large arteries are notfeasible. Therefore, native fistulas are often created to provide bloodflow access for the hemodialysis machines.

Typically, a native fistula is created by transecting a vein in thewrist near the back of the hand, freeing the vein from its connectivetissue, bringing the vein around to the palm side of the wrist adjacentan artery, and affixing an anastomosis to connect the vessels with anopen lumen to join the vein to the artery. The result is advantageouswith a vein having significantly more blood flow than normal that can beused for exchanging large volumes of blood during dialysis. The surgeonperforms the procedure by opening the skin surgically over the chosenarea and completing the procedure externally to connect the vessels.However, such a procedure can be quite invasive, resulting in increasedrisk of adverse events to the patient.

It is therefore desirable to provide a procedure and device whichcreates a native fistula with a minimum of surgical intervention, whichis less invasive and less traumatic to the patient than the presentlyutilized procedures.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method of bloodvessel transecting and anastomosis comprising inserting a cutting toolinto a first blood vessel, cutting the first blood vessel using thecutting tool from within the first blood vessel to separate the firstblood vessel into a first cut portion and a second cut portion, andfusing the first cut portion of the first blood vessel to a second bloodvessel to provide a flow channel between the first cut portion of thefirst blood vessel and the second blood vessel.

The fusing step may fuse the sides of the first and second bloodvessels, or may fuse the end of the first cut portion of the first bloodvessel to the side of the second blood vessel. The end of the second cutportion is sealed, and if the fusing is side to side, the end of thefirst cut portion is also sealed. The fusing step may be performed byradiofrequency (RF) energy, and sealing of the cut ends of the firstblood vessel may also be performed by RF energy. In one variation, thefirst blood vessel is a vein and the second blood vessel is an artery.While the typical location for this procedure is in the wrist area of apatient, other bodily locations can be effectively used and are withinthe scope of this invention. The blood vessels to be connected may beadvantageously located adjacent one another, but it should be understoodby one of skill in the art with the benefit of the present disclosurethat the procedure described herein can effectively move the first cutportion of the first blood vessel to a position adjacent the secondblood vessel even if the second blood vessel is remote from the firstblood vessel.

In one embodiment, the device for transecting a blood vessel comprises acutting tool for insertion within a blood vessel, including a cuttingmeans operative to transect the blood vessel, said cutting toolincluding a first closed position and a second open position, whereinthe cutting means is exposed to the blood vessel internal surface forcutting in the open position and shielded from the blood vessel internalsurface in the closed position.

These and other embodiments, features and advantages of the presentinvention will become more apparent to those skilled in the art whentaken with reference to the following more detailed description of theinvention in conjunction with the accompanying drawings that are firstbriefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing access to a vein in the forearm;

FIG. 2 shows the insertion of an occlusion device in the vein anddeployment thereof to occlude the vein;

FIG. 3 shows rotation and operation of the occlusion device within thevein to transect the vein;

FIG. 4 shows accessing an artery in the forearm with a catheter andcrossing one end of the cut vein over the artery;

FIG. 5 shows the introduction of electrode catheters into the crossedend of the cut vein and the adjacent artery, performing anastomosis,occluding the free end of the cut vein, and creating a lumen between thebonded vein and artery;

FIG. 6 shows the resultant structure with catheters removed;

FIG. 7 is a detail view of the deployed catheter with cutting meansexposed;

FIG. 8 is a detail view similar to FIG. 7 with the catheter closed tocover the cutting means.

FIG. 9 is a detail view of the RF electrodes positioned in the adjacentvein and artery; and

FIG. 10 is a detail view of the RF electrodes.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are identicallynumbered. The drawings, which are not necessarily to scale, depictselected preferred embodiments and are not intended to limit the scopeof the invention. The detailed description illustrates by way ofexample, not by way of limitation, the principles of the invention. Thisdescription will clearly enable one skilled in the art to make and usethe invention, and describes several embodiments, adaptations,variations, alternatives and uses of the invention, including what ispresently believed to be the best mode of carrying out the invention.

According to one embodiment of the present invention, a first phase increating a native fistula is the transection of a desired vein using anappropriate cutting device. In one variation, the vein transectingdevice employs a cylindrical cutter to slice through the vein wall fromwithin the vein, allowing for minimal surgical invention. As illustratedin FIGS. 1-3, a catheter 10 is inserted through a small incision 18 intoa patient's vein 12 in the forearm or wrist 16 thereof in a direction 14towards the patient's fingers. In this example, an occlusion device 20is inserted through catheter 10 to occlude the vein as shown in FIG. 2,and a cutter 22 is inserted through the catheter 10 to perform thetransection, as shown in FIG. 3. The forward end 24 of the catheter isclosed to protect the cutter 22, and opened as shown in FIG. 3 when thecutting is to commence to expose the cutter. Suction or vacuum may beapplied through the catheter to pull the vein wall towards the cutter,and the cutter rotated in either direction, such as in the direction ofarrow 26, to sever the vein in the desired location. The suction orvacuum which may be applied, may be applied through an inner lumen ofthe catheter shaft and serves to pull the vein into the path of therotating, cylindrical cutter.

The procedure for transecting a vein is further illustrated in FIGS. 7and 8, which show a detailed view of a representative cutter 100, vein102, catheter shaft 104, cutting means 106 and anvil 108. In the cutteropen position shown in FIG. 7, vacuum or suction is applied through thecatheter shaft 104 via vacuum or suction means 114, shown schematically,to pull the vein 102 inward. The cutting means 106 is rotated, such asin the direction of arrow 110 shown in FIG. 8, to cut the vein againstthe anvil 108 and to retract the cutter against the anvil. The vacuum orsuction means is then shut off and the cutting device removed fromwithin the vein in the direction of arrow 112, possibly with the cuttingdevice including a cut segment of the vein. The resultant cut vein hastwo cut portions, first cut end portion 102A and second cut end portion102B, as can be seen in FIG. 8.

A second phase in creating a native fistula is to make a connectionbetween the cut vein and an artery, which is illustrated in FIGS. 4-6. Acut end of the vein, such as cut end portion 102A, is brought intocontact with a selected artery, such as artery 30 shown in FIG. 4. Asmentioned, it is advantageous that the vein and artery be adjacent eachother; however, it should be understood that a connection can be madebetween a separated vein and artery not adjacent to one another bystripping away connective tissue from the vein and relocating theposition of the vein. FIG. 4 illustrates a side-to-side connection,although certainly an end-to-side connection is also possible andcontemplated by the present invention. The first cut end 102A of vein102 is mobilized with catheter 32, and the artery 30 is accessed withcatheter 34. If desired, a light 33 can be provided at the end ofcatheter 34 that is visible through the skin, and also at the end ofcatheter 32, if desired, in order to assist in locating or aligning thevein with respect to the artery. Naturally, other alignment means orvisualization techniques know to one of skill in the art can be used,including fluoroscopy, radiopaque markers, ultra-sound, etc.

In one variation of the present invention, radiofrequency (RF) energy isutilized to heat and fuse the vessels together. Tissue welding can beaccomplished with heat and pressure between two collagen structures. Thevein and artery outer layers or adventitia are composed primarily ofcollagen. When heated to between about 50° C. and 100° C. the collagenprotein is denatured which allows it to be reformed or fused together.In addition, the strong fascia between the vein and artery is collagen,which is quite pronounced in the wrist area, and provides a weldingmedium to assist in achieving a better bond. Thus, as shown in FIG. 5, avein electrode catheter 36 may be introduced into the first cut end 102Aand an artery electrode catheter 38 may be introduced into artery 30 toperform an anastomosis between the first cut end 102A and artery 30. Inone variation, this procedure includes the occlusion of the free end offirst cut end 102A at first end portion 40, followed by the creation ofa lumen 42 by connecting first cut end 102A of vein 102 with artery 30along the sides thereof. The final structure can be seen in FIG. 6. RFenergy may also be used to occlude the second end portion 44 of secondcut end 102B (FIG. 8).

FIGS. 9 and 10 show vein electrode 32 and artery electrode 34, with FIG.9 showing the electrodes in position in vein 102 first cut end 102A andin artery 30, and FIG. 10 showing the electrodes removed from thevessels with insulation 46 thereover. Alignment means may be provided onthe RF electrodes to aid in alignment for the anastomosis, as forexample post 48 on electrode 32 and opening 50 on electrode 34.Naturally other alignment means can be provided and are within the scopeof this invention. RF energy at a frequency of from approximately 400 to600 KHz, and generally at a frequency of about 500 KHz, is used in oneembodiment of the present invention. In one variation, bi-polar RFenergy is utilized and the desired tissue is simply positioned betweenthe two electrodes as shown. The current flows from one electrode,through the tissue which has a resistance, to the other electrode. Theresistance of the tissue produces the heat which fuses the tissuestogether and also forms the desired lumen. Pressure may be appliedbetween the electrodes. Following the procedure, pressure is releasedafter a cooling period and the electrode catheters are withdrawn,leaving the vein attached to the artery.

Thus, the present invention advantageously transects the vein in asimple, convenient manner, and bonds the vein to the artery and forms alumen therebetween, also in a simple and convenient manner.

This invention has been described and specific examples of the inventionhave been portrayed. While the invention has been described in terms ofparticular variations and illustrative figures, those of ordinary skillin the art will recognize that the invention is not limited to thevariations or figures described. In addition, where methods and stepsdescribed above indicate certain events occurring in certain order,those of ordinary skill in the art will recognize that the ordering ofcertain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certainof the steps may be performed concurrently in a parallel process whenpossible, as well as performed sequentially as described above.Therefore, to the extent there are variations of the invention, whichare within the spirit of the disclosure or equivalent to the inventionsfound in the claims, it is the intent that this patent will cover thosevariations as well.

1. A method of blood vessel transecting and anastomosis, comprising:inserting a cutting tool into a first blood vessel; cutting the firstblood vessel using the cutting tool from within the first blood vesselto separate the first blood vessel into a first cut portion and a secondcut portion; and fusing the first cut portion of the blood vessel to asecond blood vessel to create a flow channel therebetween.
 2. The methodaccording to claim 1, further comprising the step of moving the firstcut portion to a position adjacent the second blood vessel.
 3. Themethod according to claim 1, further comprising the step of insertingseparate catheters into said first and second blood vessels, saidcatheters comprising alignment means to align the first and second bloodvessels.
 4. The method according to claim 1, further comprising the stepof sealing the exposed ends of the first and second cut portions.
 5. Themethod of claim 4, wherein the sealing step is performed byradiofrequency energy.
 6. The method according to claim 1, wherein thefusing step is performed by radiofrequency energy.
 7. The methodaccording to claim 1, wherein a side of the first cut portion is fusedto the second blood vessel.
 8. The method according to claim 1, whereinan end of the first cut portion is fused to the second blood vessel. 9.The method according to claim 1, wherein the flow channel is formed byradiofrequency energy.
 10. The method according to claim 1, wherein thefirst blood vessel is a vein and the second blood vessel is an artery.11. The method according to claim 1, wherein the blood vessels arelocated in the forearm of an individual.
 12. The method according toclaim 1, further comprising the step of inserting separate electrodes inthe first and second blood vessels to perform the fusing step.
 13. Themethod according to claim 12, wherein alignment means are provided onsaid separate electrodes to align said electrodes for the fusing step.14. A blood vessel transecting device comprising a cutting tool forinsertion within a blood vessel, including a cutting means fortransecting the blood vessel, said cutting tool comprising a firstclosed position and a second open position, wherein the cutting means isexposed to the blood vessel internal surface for cutting in the openposition and shielded from the blood vessel internal surface in theclosed position.
 15. A device according to claim 14, wherein the cuttingtool includes an anvil which is movable with respect to the cuttingmeans such that in operation the cutting means transects the bloodvessel against the anvil.
 16. A device according to claim 15, furthercomprising a catheter shaft connected to said cutting tool, and means topull the blood vessel inward applied through the catheter shaft.
 17. Adevice according to claim 16, wherein the cutting means is rotatableagainst the anvil to transect the blood vessel.
 18. A device accordingto claim 17, wherein the cutting means is cylindrical.